to the trial of notorious mob boss whitey bulger. And this evening, a plot twist worthy of a detective novel. A man who had been in that courtroom waiting decades to testify against bulger, suddenly found dead. Abc's ron claiborne covering the case. Reporter: Every day for weeks, stephen rakes showed up at whitey bulger's trial, awaiting the day that he could testify against the former reputed boston mob kingpin. Bullet-piercing eyes. There is no heart. He probably sleeps in an ice chest. Reporter: Every day, until last wednesday, when rakes was found dead on the side of the road in a boston suburb -- no wallet, no i.D., No signs of trauma. Originally, police thought that rakes' death was a suicide, but increasingly, it appears it was not suicide. It was not natural causes, but something suspicious. Although an autopsy was inconclusive, investigators now believe his body was dumped where it was found. Rakes had been expected to testify that 30 years ago, bulger extorted him into selling his south boston liquor store. But the same day rakes disappeared, prosecutors decided not to call him to the stand. He was very much looking forward to testifying. Reporter: At bulger's trial friday, dramatic testimony from confessed mob boss and bulger crony, stephen, "the rifleman" flemmi, who said bulger personally murdered flemmi's girlfriend after the two men decided she knew too much. Flemmi, he grabbed her around the neck and strangled her. Prosecutor, what did you do? Flemmi, nothing. Also coming out, this astounding allegation by flemmi that they made regular cash payments to half a dozen BOSTON FBI AGENTS IN THE '70s AND '80s. He said that one of them was so grateful that he gave them a case of military-grade plastic

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